Process for reclaiming vulcanized-rubber waste.



' C. S. HE'LLER. PROCESS POB BBOLAIMING VULOANIZED RUBBER WASTE.

APPLICATION rILn rpn. z5, 1910.

Patented Dec. 13, 1910.

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UNITED sTATEs APATENT oEEIcE.

CHARLES S. HELLER, F BARBERTON, OHIO, ASSIGNOR T0 THE MOORE ARCHITECTURAL AND ENGINEERING COMPANY, OF AKRON, OHIO, A CORPORATION OF OHIO.

.To all whom 'it may concern:

Be it known that I, CHARLES S. HELLER, a citizen of the Uni-ted States, residing at Barberton, in the county of Summit and State of Ohio, have invented new and useful Improvements in Processes for Reclaiming Vull canized-Rubber Waste, of which the follow` ing is a specification.

This invention relates to improvements in processes -for re-claiming rubber`wastef and the vobject thereof is to provide a new; and improved process for removingfrom the rubber waste the materials which have' been previously mixed with the gum to producevul'canization thereof, and other materials added to the gum to increase the weight, reduce the cost, 'or c improve the qualities of the vulcanized article and at the same time to eliminate as far as possible the fibrous material which has been incorpo rated therewith during the manufacture thereof, especially in the form of fabric.

This improved process for re-claiming rubber Waste, comprises the subjecting of the rubber waste, preferably in a comminuted condition to the action of a re-claiming solution in the presenceof heat and simultaneously subjecting the same to an electrolytic action of a current of electricity of a determined degree of intensity and quality, passed through the re-'claiming solution to assist in the 4disinte, rration of the rubber waste and the removal and elimination therefrom of foreign matters contained therein, and followed by subjecting thel rubber to a thorough cleansing 'operation to lsubsequently remove from the rubber waste 4all traces of the re-claimingsolution, which in -this process is of such a nature that its presence in the finshed rubber will be deleterious thereto. l

In carrying into effect my improved process I'employ certain mechanical structures lby which the subjecting of the rubber waste to the re-claiming process is carried out and the subsequent elimination of the re-claiming solution from the rubber waste is accomplished.

A preferred form of apparatus for carryling out my improved process is shown in the accompanying drawing Whlch forms a part hereof.`but ity is'to be understood that various changes and modifications may be employed forcarrying out my process withoutdeparting from the scope of this invention.

Specification of Letters Patent.

Application filed 'February 25, 1910. Serial No. 545,960.

Patented Dec. 13, 1910.

Briefly describing the mechanical stirac-l aEIssuEo ture used in connection with this process the reference numeral 1 denotes a metallic cyl`-l inder, preferably supported by one. or more brackets 2 secured to the outer face of the cylinder land resting upon I beams The' upper end of the cylinder 1 is usually closed by means of a head 4 secured to the upper end 'of the cylinder l by rivets 5 and the head is further provided with a steam inlet pipe (.l The lower end of the cylinder' l is provided with a conically-formed bottom 7 to which is secured a member 8 proy vided with a central aperture communicating through a suitably-formed opening in the coni Ial end of the cylinder with the interior thereof. The member 8 is provided with an enlarged threaded recess to receiy'e a second member 9 exteriorly-threaded to cooperate therewith and forma stuiiing box for the end of a pipe 10 positioned therein, the upper end of the latter extending into the interior of the cylinder 1. lVithln the cylinder l and spaced therefrom to form between them a steam chamber is a tank 11 t-he upper end of which is closed by ahead 12 and having at its lower end a conicallyformed portion 13 approximately-parallel with the conical end of the cylinder 1 and with a depending pipe at the apex thereof connnunicating with the upper end of the pipe 10. The heads 4 and l2 of the cylinder 1 and tank 1l areA provided with alined openings and between said heads and surrounding said openingsds an apertured collar let the aperture 15 in which constitutes an opening through which 'access may be had to the interior of the tank 11. The opening 15 is closed through the medium of a swinging door 16, preferably hinged to the inner face of the head 12 and normally held in a closed position by means of a threaded hook bolt 17 engaging said door and rotatably-mounted in a brace 18 bridging said opening and mounted on the outer face of the head 4, said bolt being drawn up to close said door by means of a hand nut 19.' The side walls of the cylinder l and tank 11. are provided with laterally-registering openings and between them and having an opening in registering relation therewith is a collar 20. Secured to theouter face of the cylinder l by means of bolts 21 is the flanged end of a pipe 22 having an elbow 23 from which depends a vertical portion connecting with a horizontal pipe`24 by an elbow. Extending through a lug 25 formed on the latter elbow at the lower end of the pipe 22 is a shaft( 26 mounted in bearings 27 and provided at its inner end with a propeller 28. The lug 25 is provided with a stuffing box 29 to prevent leakage of liquid from the pipe 22 outwardly along the shaft ranged vertically and centrally with respect to the tank 11, the interior of the pipe 31 being in open communication with the interior of the pipe 22. Positioned centrally within the tank 11 and supported by spacing members 33 is an inverted, conically-forined member 34 having an opening 35 at the. apex thereof in alinement -with the pipe 10. The inverted,- conically-formed portion 34 is provided with an upwardly-extending cylindrical portion 36. 4Supported by the cylindrical portion 36 is an annulus 37 preferably formed of zinc and insulated from the member 36 by a member 38 and preferably somewhat smaller in diameter than the member 36. Connected with the zinc annulus 37 is a wirev 39 passing through the wall of the tank 11 and cylinder 1 and protected therefrom by lan insulating member 40 and connecting with one pole of an electric currentgenerating device 41, from the opposite pole of which extends another wire 42' to the ground 43. The cylinder 1 is connected with the ground by a wire 44. The ground 43 is l preferably employed to complete the circuit between thewires 42 and 44, but .ofcourse any other means for uniting the outer ends of said wires may be employed which is deemed best. Arranged centrally within the pipel32 is a vertically-shiftable valve stem 45 having at its lower end a valve 46, arranged when in its operative position to close the opening 35 in the conical member 34, and when raised to an inoperative position to permit passage of a fluid through said opening. The upper end of the valvestem 45 passes upwardly through-the heads 4 and 12 of the cylinder 1 and tank 11, respectively, and is connected with one end of an operating lever 47 pivotally-mounted on a post 48, which in turn is mounted on the upper face of the head 4 of the cylinder 1. The opposite end of the lever 47 is provided with a' hand grasp by which the valvestem 45 and valve 46 are shifted.

The cylinder 1 and tank 11 are arranged y to constitute'a receptacle for a re-claiming solution and the comminuted rubber waste to be acted upon by said solution, and the space between the cylinder 1 and tank 11 constitutes a heating chamber which the contents of the receptacle are brought to a desired temperature to carry out the process to be hereinafter described.

Communicating with the pipe 24 at any desired point is a discharge pipe 49 proapex to receive a vertically-shiftable" up.

wardly-extending pipe 56 having secured to the lower end thereof a drum-shaped member 57 formed of Wire cloth from which depends a drain tube 58 extending into and telescoping the pipe 54. Mounted on the upper end of the pipe 56 is a cap 59 provided with an aperture through which extends a tube 60 held in position by nuts 61 placed above and y below the cap 59. downwardly into the-member 57 and terminates in a bent nozzle 62 provided with` a plurality of minute openings so placed and shaped that jets of fluid issuing therefrom will impinge against the sides ofthe drumshaped member 57 and tend to remove all particles of matter adhering to the outer surface thereof. This nozzle conforms generally in shape with the side walls of the member 57 and is arranged to be revolved with the pipe 6() as an axle. Surrounding the /cylindrical portion 51 of the cleansing tank is a steam pipe 63 from which extend inwardly through the wall 51 of the tank a plurality of steam pipes 64.V .Ihese pipes 64 are preferably arranged radially to the cleansing tankand lie on the bottom thereof 4and each is provided with a plurality of openings 65. The bottom 53 is provided near its apex with a discharge opening 66 closed by a gate 67.

In carrying out this process a sufficient quantity of re-claiming solution and comminuted rubber waste is placed within the receptacle to cover the pipe 31', previous to which the valve 46 is shifted to close'the opening 35. The re-claiming solution which I preferably use for each one hundred pounds of comminuted rubber waste is six hundred (600). pounds of water by weight, twenty-one (21) pounds of sodium hydrate, (NaOH), or potassium hydrate (KOH) and one (l) pound of ferrie sulfate, Fe2(SO4). The solution in the tank is kept constantly heated by live steam The pipe 60 extends introduced to the steam chamber between the'cylinder 1 and tank 1l from the pipe 6. rl`he efficiency of the action of the re-claiui ing solution upon the comminutedrubber waste during the carrying out of this process is increased by constantly maintaining the contents of the tank in the receptacle in a heated condition, preferably from 330 to 3700 F., but experience has found that 360O is the preferred temperature, which is accomplished by introducing steam to the steam chamber at a pressure of from ninetyfive (95) to one hundred and sixty (160) pounds. During the time that the comminuted rubber waste and solution are within the receptacle and subjected to the action ofboth heat and pressure, motion is communicated to the shaft 26 by meansl of a belt applied to the pulley v3() to produce sufficient revolution of the propeller 28 to cause the solution and comminuted rubber waste to pass through the pipe 10 in the direction of the arrows, and as rapidly as said solution passes through the pipe 10 it escapes through'the space between the conical portion 13 of the tank 11 and the j conical member 34 and from thence upwardly around the zinc annulus 37 and from thence into the interior of the same..

The action of the propeller in forcing the solution and comminuted rubber waste through the pipe 10 withdraws the solution and comminuted rubber waste contained in the conical member 34 upwardly through the pipes 32 and 31 into the pipe 22 from whence it descends to the pipe 24 and is again forced upwardly through the pipe 10. During the passage of the solution and comminuted rubber waste it is constantly agitated and is brought into immediate contact with the wall of the tank 11, especially its conical portion 13, so as to receive all possible heat conducted through the wall of the receptacle .from the steam chamber and 1s thus constantly maintained in a heated condition and under pressure by reason of the temperature to which the solution is raised.- During its movement with the solution, the rubber waste in passing between the'zinc annulus 37 and the wall of the tank 11 1s subjected to the action of an electric current generated by the cin'rent-generating device 41, which is connected both with the zincannulus by the wire 39 and by other current-conducting means with the receptacle containing the solution and from which the zinc annulus is insulated, the zinc annulus constituting to a certain extent a cathode and the wall of the receptacle an anode.

Experience has shown that the maj or por-V tion of vulcanized rubber waste subjected to the action of the re-claiming process car- 'ries a large percentage of mineral and metallic matter, especially sulfur, and the 'lh'e sulfur which is removed from the rubber waste is, through the influence of the chemical solution in which it is contained, together with the electrolytic action of the current, converted into a soluble combination which is carried away in the form of a solution and without going into a detailed description of the peculiar electrolytic action of the current passed through the solution and acting upon the rubber waste, it will be stated that remarkable results have been obtained by the use of an electric current in the elimination of the deleterious matters carried by the rubber which have been incor orated therewith previous to the vulcanlzation thereof and the removal of which conditions the rubber and prepares it for use in as nearly as possible its original gummy condition which it possessed previous to its initial vulcanization.

When the described process of agitating comminuted rubber in a re-claiming agent within a receptacle in the presence of heat and under pressure and subject to the action of an electric current has been carried on a sufficient length of time, which is usually from ten to twenty-four hours, the valve 46 is raised to permit the matter contained in the conical member 34 to pass'into the pipe 10 and from thence to the pipe 24. The gate 50 is then opened allowing the solution and rubber waste to discharge into the cleansing tank 11 through the pipe 49.

The cleansing tank may preferably be filled with pure hot water to remove as far as possible all chemicals, especially the caustic alkalies used for re-claiming the rubber and separating the deleterious matters therefrom. l

In order to increase the effectiveness of the water in the cleansing operation, live steam is turned into the annular pipe 63 from whence it passes to the pipe 64 and escapes through the orifices 65 and the force of the steam in jets issuing from the orifices 65 will tend to kee the solution in the cleansing tank centra ly agitated. After the cleansing process has been carried on for a sufficient length of time the member 57 and pipe 58 are lowered sufiiciently to cause the member 57 to be submerged in the solution which passes through the foraminous wall thereof and escapes through the medium of the pipe 58, leaving the comminuted rubber waste within the cleansiner tank. After the major portion of the liquld has been removed by the member 57, the latter is raised and fresh water turned in .the pipe 60 from whence it escapes through the orifices in pipe 63 and the process renewed and this isv repeated until all the solution employed for re-claiming the rubber, especially the caustic alkali, has been removed from the comminuted rubber waste, after which and i preferably while there is a considerable quantity of water in the cleansing tank, the gate 67 x is opened and the water and comminuted rubber particles are permitted to escape by the discharge pipe 66 onto suitable screens, after which the rubber waste is dried and is ready for use.

It will be apparent that the thorough vcleansing of the rubber waste after the re-` claiming process has. taken place becomes absolutely necessary in order to arrest disintegrating action of thecaustic alkalies employed for` removing the sulfur and other substances incorporated with the rubber gum previous to the vulcanization thereof, and at the same time a large percentage of the fabric contained in the rubber waste is also washed therefrom.

It will be especially noted that the agitation of the re-claiming solution within the receptacle is of such a nature as to expose all particles of the comminuted rubber to the action of the electric current described and experience has shown that a current of 4 6 /10 volts and from 700 to 1000 amperes in strength, is preferred in producing the disintegration necessary in the re-claiming process and to eectually remove the metal and mineral matter contained in the rubber.

'- I claim:

1. That improvement in the artof reclaiming rubber which consists in subject ing vulcanized rubber waste to the action of a solution containing av caustic alkali and ferric sulfate in the presence of heat and under pressure and subjecting said waste simultaneously to agitation and the action of an electric current and afterward washing said waste to remove the re-claiming agents therefrom.

2. That improvement in the art of reclaiming vulcanized rubber waste which consists in agitatin 'said rubber waste in a comminuted con ition while in a solution containing a caustic alkali and ferric sulfate in a heated condition and under pressure and simultaneously subjecting said waste to the action of an electric current and afterward washing the same to remove the re.- claimingl agents therefrom.

3. That improvement in the art of reclaiming rubber which consists in subjecting vulcanized rubber waste, in a comminuted condition to the action of a solution containing a caustic alkali and ferric sulfate, continuously lheating said solution and sub jecting the same to pressure and agitation and simultaneously to the action of an electric current and afterward thoroughly washing said waste to remove all trace of'the reclaiming agents therefrom.

4. That improvement in the art o-f re.

claiming rubber which consists in commingling vulcanized rubber waste in a comminuted condition with a solution containing a caustic alkali and ferric sulfate, forcing said commingled waste and solution continuously throu h a heated receptacle to maintain said so ution and waste at a proper temperature to cause'the separation of the vulcanizing agents therefrom and simultaneously subjecting said waste to the action ofl an electric current and afterward withdrawing said solution and rubber waste from said receptacle and washing the same to remove the re-claiming agents therefrom.

,5. That improvement in the art of reclaiming rubber which consists in commingling vulcainzed rubber waste in a. comminuted'condition with a solution containing for each one hundred (100) pounds of rubf' ber waste twenty-one (21) pounds of a caustic alkali, six hundred (600) pounds of water and one (l) pound of ferric sulfate, maintaining said solution in a heated condition and under pressure and subject to agitation during the re-claiming process and simultaneously passing an electric current through said rubber waste while contained in said solution and afterward washing said solution to remove the re-claiming agents therefrom.

Inptestimony whereof I have hereunto set my hand inpresence of two subscribing wit-I nesses.

CHARLES S. HELLER. 

